1. Field of the Invention
The present invention relates to a magnetooptic recording and reproducing apparatus which records information by projecting a focused optical beam on a recording medium and simultaneously applying a magnetic field to the recording medium and reproduces information recorded on the medium, and more particularly, to a portable magnetooptic disk player which uses a magnetooptic disk cartridge in which a magnetooptic disk is rotatably received.
2. Description of the Related Art
Generally, a magnetooptic disk has recording layers in which desired information is recorded and the recorded information is reproduced using a magnetooptic disk player which has an optical pickup for the projecting of a focused optical beam and a bias magnet for applying a magnetic field. The recording layers, for example, are composed of a magnetic material, such as TbFe or TbFeCo. This magnetooptic disk is received in a caddy to form a disk cartridge so that the disk is loaded in a disk drive together with the caddy.
Recently, a magnetooptic disk cartridge called a "minidisk" (64 mm diameter) was placed on the market by Sony, and the development of a player therefor has progressed actively. There are two types of currently available minidisks: a recordable type shown in FIGS. 1A and 1B and a reproduction-only type shown in FIGS. 2A and 2B.
Referring to FIGS. 1A and 1B, the recordable minidisk 1 has a cartridge cell 2 having two openings 3 and 4 on respective sides thereof and a shutter 5 which moves along a sliding groove 6 so as to open and close openings 3 and 4. Both sides of a disk 9 in cartridge cell 2 are exposed through openings 3 and 4. In FIGS. 2A and 2B, the reproduction-only minidisk 1' has a cartridge cell 2' having an opening only on one side thereof and a shutter 5' which moves along a sliding groove 6' so as to open and close opening 3'. Thus, only one side of disk 9' is exposed through opening 3'.
Arrows 7 and 7' on the upper surface of cartridge cell 2 and 2' of minidisks 1 and 1' each depict the direction of insertion into a player. Recording and reproducing detection grooves 8 and 8' each having a different size are formed on the lower surface of cartridge cell 2 and 2' so that it can be determined whether an inserted minidisk is a recordable type or a reproduction-only type based on the size thereof. Loading grooves 10 and 10' are provided at the right and left sides of the lower surface of cartridge cells 2 and 2'. A plurality of cartridge loading grooves 11 and 11', for loading the disk cartridge into a deck, are provided on the lower surface of cartridge cells 2 and 2'.
A portable player (Sony model MZ-1) is now available as a recording and reproducing apparatus for the above-described minidisks. This player is formed with a slot into which the minidisk can be inserted by means of a "slot-in" method, and includes a spindle motor which rotates the inserted minidisk, an optical pickup which projects a focused optical beam onto one side of the disk, and a magnetic head which applies a magnetic field to the other side of the disk. The cartridge of the minidisk inserted into the slot is loaded into a deck, in the state where the shutter is pushed aside to provide access to the opening. Meanwhile, the disk in the cartridge is loaded on a turntable rotated by a spindle motor. When choosing the reproducing mode with respect to the rotating disk, only the optical pickup operates and the magnetic head is raised away from the disk. When choosing the recording mode, the magnetic head is lowered by a motor, to be disposed near the surface of the disk, and move together with the optical pickup. However, with a reproduction-only minidisk loaded, the magnetic head does not descend even if the recording mode is selected.
In general, it is desirable that a portable player be lightweight and compact and consume little electrical power. However, in the case of the Sony minidisk player, it is difficult to make the minidisk player small and lightweight because the minidisk inserting structure (using the above-noted slot-in method) and the magnetic head ascending/descending structures are complicated and require a large space. Also, as the minidisk is inserted/extracted and the magnetic head ascends/descends by separate driving means, power is consumed excessively.
An apparatus for mechanically solving the above problems is shown in FIGS. 3 and 4. Here, when magnetooptic disk cartridge 1 is inserted into cartridge holder 20, locking protrusion 55 of drawing-out member 50 engages with locking pin 61, and locking portion 95 of slide locking member 90 engages with locking pin 94 formed on cartridge holder 20. As cartridge 1 is inserted, a protruding pin 85 installed on contacting end 54 of drawing-out member 50 is pushed, so that supporting stick 86 for supporting protruding portion 45 is pushed back. Therefore, magnetic head 30 is lowered to make contact with the upper surface of magnetooptic disk 9 in disk cartridge 1. When cartridge holder 20 is in the open state, if disk cartridge 1 is drawn out to be exchanged with another disk cartridge, there is a potential risk of damaging the lowered magnetic head 30 due to contact with the moving cartridge.